Helotrephes steiningeri sp. n., and notes on two further Helotrephini spp. (Heteroptera, Helotrephidae) from Thailand and West Malaysia

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1 Linzer biol. Beitr. 32/ Helotrephes steiningeri sp. n., and notes on two further Helotrephini spp. (Heteroptera, Helotrephidae) from Thailand and West Malaysia D. KOVAC & M. PAPÄCEK A b s t r a c t: Helotrephes steiningeri sp. n. from Thailand, the largest helotrephid species found so far, and Helotrephes flaviceps rompinensis ssp. n. from West Malaysia are described. Helotrephes flaviceps flaviceps ZETTEL & POLHEMUS 1998 is recorded from West Malaysia for the first time. Some aberrant characters of the male genitalia of Hydrotrephes septentrionalis ZETTEL 1998 from Thailand are discussed. Key words: Helotrephidae, -Helotrephes steiningeri, new species, Helotrephes flaviceps rompinensis, new subspecies, Hydrotrephes septentrionalis, variability, Thailand, West Malaysia. Introduction Species of the genus Helotrephes inhabit streams and rivers in the East-Oriental region. This genus has recently been revised by ZETTEL & POLHEMUS (1998) and contains sixteen species and three subspecies. In the present paper we describe the following new Helotrephes taxa: H. steiningeri n. sp. from North Thailand and H. flaviceps rompinensis n. ssp. from West Malaysia. Furthermore, we report on the first record of H. flaviceps flaviceps from West Malaysia and on variability of some characters of the male genitalia in Hydrotrephes septentrionalis. The genus Hydrotrephes also belongs to the tribe Helotrephini and mainly occurs in lotic habitats in the Oriental Region and Wallacea. It has recently been studied by POLHEMUS (1997), ZETTEL (1998, 2000), and NIESER & CHEN (1999). Measurements and abbreviations All measurements are in millimetres. Body length and maximal width have been measured in all specimens. brach macr NHMW SMF ZRC brachypterous macropterous Natural History Museum, Vienna, Austria Senckenberg Research Institute (Senckenberg Museum Frankfurt), Frankfurt am Main, Germany Zoological Reference Collection, Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore, Singapore

2 266 Helotreplies steiningeri sp. n. (Figs 1-6) Type material: holotype (brach. 6): Thailand, Chiang Mai Province, stream near Pong Duet Hot Springs, on the roadfromchiang Mai to Mae Hong Son, between submerged tree roots, 8 Apr. 1998, A19, leg. D. Kovac (SMF); paratvpes: 36 6, 4op (all brach.), same locality data as holotype; Id, 2p p (all brach.), same locality data as holotype, A19B (SMF); same locality, 6 Apr. 1999, 266, l9,a202/99,(smf). Description: Body length of , of $ $ , body width of both sexes Ground colour yellowish to yellowish brown. Colouration variable in different specimens; it depends probably on the level of sclerotization and pigmentation of adults of "different age". Cephalonotum with complex patterns and scattered weakly to strong dark markings between and behind eyes; clypeal area and anterior part of frontal area yellow; posterior area of cephalonotum with stripe-like complex pattern in dark specimens. Mesoscutellum a bit lighter than hemelytra, with dark anterior part in dark specimens. Both mentioned body regions with weakly dark scattered punctations (inflight specimens) or dark patterns respectively (in dark specimens). Venter yellowish brown. Legs and antennae yellow. Rostrum: basal part yellow, distal part yellowish brown to dark brown. Cephalonotum convex, shining, set with small alveoli in dorsal view, broader than long (length: , width: ); lateral margins behind eyes carinate. Eye length : width, Interocular distance: Pronotal plate with deep slightly asymmetrical notch, and with sharp posterior angle (Fig. 1). Posterior corner of the notch with posteriorly localized, roundly curved lamela (Fig. 1). Mesoscutellum weakly shining, hemelytra shining to opaque; both these body parts with small depressed alveoli, each with one short seta. Mesoscutellum length : width, 1.95 : Ventral midsternal carina: prosternal part with two caudally extended tips; apical tip of mesosternal carina directed anteriad; metasternal carina with posteroventrally oriented tip, carina of abdominal segment 2 relatively long and low (Fig. 2). Male: aedeagus long, distally slender, with large apical plate which is thicker apically (anteriorly) than subapically (posteriorly) from lateral view (Figs 3a, b); right paramere slightly curved, subapically slender, apically with anteriorly oriented dilatation, posteroapically with relative long setae (Figs 4a, b); left paramere straight to slightly posteriad curved, relatively hirsute, with distinct posterobasal lobe, anterior outline of its apex round, posterior outline truncate (Fig. 5). Female: abdominal sternum 7 (= subgenital plate) with broad tongue-like middle lobe (Fig. 6); proximal part with long pilosity, distal part with short pilosity. Comparative notes: Helotrephes steiningeri agrees with the characteristics of the Helotrephes sausai group (see ZETTEL & POLHEMUS 1998, p. 115). It is similar (and probably also the closest relative) to H. major in the shape of the aedeagus but it differs from this species, and also by H. monticola, especially by the slightly curved left paramere and the posteroapical truncation of right paramere in males, and by short, tongue-like middle lobe of abdominal sternum 7 in females. H. steiningeri is distinguishable from H. sausai by the long aedeagus, the shape of both parameres in males, and by the narrower midle lobe of abdominal sternum 7 in females. H. steiningeri differs from all other species of the genus by the strictly caudally oriented two tips of prosternal midventral carina of both sexes, and the shape of therightparamere. H. steiningeri is the largest known species of Helotrephidae. Habitat: Helotrephes steiningeri was found between submerged tree roots and only occured at locations with fast flowing water. It was collected together with Helotrephes australis.

3 267 Distribution: Thailand, Chiang Mai Province. Etymology: Named in honour of Prof. Dr. F. Steininger, the head of the Senckenberg Research Institute, who made it possible for D. Kovac to go on a field trip to Thailand during which the new species was found. Helotrephesflavicepsflaviceps ZETTEL & POLHEMUS 1998 HelotrephesflavicepsZETTEL & POLHEMUS 1998: 131. Material examined: holotype 6 (brach.): "Thailand: Mae Hong Son ProvA 17rd. km N Mae Hong Son\ Mok Cham Pae, nr. Fish Cave\ , leg. H. Zettel (12b)" (NHMW); paratype: 1 5 (brach.), the same locality data as holotype (NHMW); further material: 2<J d, 2 o o (all brach.), "21 Xu 1997 ThaildA ca. 12 km N of.\ Mae Hong Son", 'Tarn Pia Resort\ at Tarn Pia River\ Dr. W. Ullrich leg.", N '34.2"\ E '16.7""Dr. Wolfgang \ULLRICH\ collection" (NHMW); 266, N. Thailand, Nam Khong River, 14 Apr. 1999, between submerged plants at river bank, A75/99, leg. D. Kovac, (SMF); 16, 2p o, N. Thailand, 9 May 1999, Nam Khong River, between submerged plants at river bank, A355/99, leg. D. Kovac, (SMF); 1<J, 2o $, S. Thailand, 23 Oct. 1999, Narathivat Prov., Ban Sac, LHK 0402, leg. H. K. Lua, (ZRC); 266, 1 o, W. Malaysia, 21 Oct. 1999, Terrenganu, Sekayu, Sungei Brang, LHK 0401, leg. H. K. Lua., (ZRC). Diagnosis and distribution: see ZETTEL & POLHEMUS (1998, p. 131). Helotrephes flaviceps rompinensis ssp. n. (Figs 7-10) Type m a t e r i a l: holotype 6 (macr): W. Malaysia, Rompin-Endau-Expedition, Sungei Kinchin, at the Base Camp, between submerged plants at the river bank, 19 May 1988, Alt7, leg. D. Kovac (SMF); paratvpes: 16, 2o o (all brach.), same locality data as holotype, Alt7/Alt7B (SMF); \6 (macr.), 266 3oo (all brach.), W. Malaysia, Rompin-Endau-Expedition, Sungei Kinchin, between submerged plants, Alt8, 23 May 1988, leg. D. Kovac (SMF). Description and comparative notes: Similar to the nominate subspecies (see and cf. ZETTEL & POLHEMUS 1998; pp. 191, 132; Figs 84-86, 94, 96, 100, 107) described from Thailand, and differing only in the following characters: Body size of both macropterous as well as brachypterous morph smaller than in brachypterous morph of H. flaviceps flaviceps. Macropterous male, length: , width: ; brachypterous specimens of both sexes, length: , width: Male: aedeagus apically somewhat narrowed, its apical plate somewhat curved (Figs 7a, b); right paramere only slightly twisted, with minute anteroapical club-shaped tuberculate process, strongly hirsute (Figs 8a, b), apical hook lacking; left paramere postefodorsally rounded, without anterobasally oriented lobe and posterobasal lamela, apically more rounded, without tip pointing outline (Fig. 9). Female: slightly asymmetrical abdominal sternum 7, the same ground shape as in nominate subspecies, but differing by blunt unconspicuous tip of hind margin of middle posterior lobe, and by more developed anterolateral lobe of left margin of the basal part of this sclerite (Fig. 10, see black arrow). Note: The anteriorly pointing left margin of posterior midle lobe of female abdominal sternum 7 (Fig. 10, see white arrow) is not a differential character from H. flaviceps flaviceps. The same structure was also ascertained in the type material of the nominate subspecies.

4 268 Discussion: H.flaviceps rompinensis was established as a new subspecies, because of the shape of male terminalia, female abdominal sternum 7, and the differences in body size. These characters are constant in specimens from the Rompin district in W. Malaysia. No diagnostic characters could be found in colour, shape of pronotal plates, and midstemal carinae. H.flaviceps rompinensis occurs allopatrically with H.flavicepsflaviceps. Distribution: W. Malaysia, Pahang. Etymology: Named after the type locality, the Rompin district in Pahang. Notes on some aberrant characters of male terminalia in Hydrotrephes ZETTEL 1998 (Figs 11,12) septentrionalis Material examined: (a) aberrant: IS 6 (brach.), N. Thailand, Pai River, between submerged plants at river bank, 7 Sept. 1998, Aqll; 4dd (brach.), N. Thailand, 8 Sept. 1998, Nam Khong River, between submerged plants at river bank, Aq20; 2 5 o, N. Thailand, 8 May 1999, Nam Lang River, between submerged plants at river bank, A339/99; 26 6, 3 Q 0, N. Thailand, 9 May 1998, Nam Khong River, between submerged plants at river bank, A355/99. All specimens leg. by D. Kovac and deposited at SMF. (b) not aberrant: holotype and paratypes deposited at NHMW (see ZETTEL 1998, p. 131). Aberrant characters: Not only apical part of the right paramere can be aberrant as ZETTEL (1998, Fig. 7) depicts but also anterobasal part is variable. It can be distinctly incised in some specimens as it is illustrated in Figs lla, b, c. Posterobasal part of the left paramere can be reduced to various degree (compare ZETTEL (1998, Fig. 8) and Figs 12a, b of this paper- see black arrows). The outline of apex of the aedeagus (see ZETTEL 1998, Fig. 6) is not variable; it is a constant and reliable diagnostic character of//, seplentrionalis. Zusammenfassung Helotrephes steiningeri sp. n. aus Thailand und Helotrephesflavicepsrompinensis ssp. n. aus West Malaysia werden neu beschreiben. H. flaviceps flaviceps wird zum ersten Mal aus West Malaysia gemeldet. Einige variierende Merkmale der männlichen Genitalien von Hydrotrephes septentrionalis aus Thailand werden diskutiert. Acknowledgements Damir Kovac thanks the Malaysian Nature Society for the opportunity to participate in the Rompin- Endau Malaysian Heritage and Scientific Expedition in 1989 and the German Academic Exchange Service (DAAD) for financing the field trip to Malaysia. Miroslav PapäCek thanks Herbert Zettel for the access to the famous collection of Helotrephidae in Museum of Natural History in Vienna, and for notes on the manuscript. He is also indebted to the Grant Agency of the Czech Republic for the financial support of this study by grant No 206/98/0160.

5 269 References NIESER N. & CHEN P.P. (1999): Sixteen new species of Nepomorpha mainly from Sulawesi. Notes on Malesian aquatic and semiaquatic bugs (Heteroptera), VIII. Tijdschrift voor Entomologie 142: POLHEMUS J.T. (1997): Seven new species of"hydrotrephes CHINA (Helotrephidae: Heteroptera) from Sulawesi. Tijdschrift voor Entomologie 140: ZETTEL H. (1998): Four new species of Hydrotrephes (Heteroptera: Helotrephidae) from Thailand and Laos. Entomological Problems 29: ZETTEL H. (2000): Erster Nachtrag zur Bearbeitung der Helotrephini Thailands (Heteroptera: Helotrephidae). Linzer biologische Beiträge 32/1: ZETTEL H. & J.T. POLHEMUS (1998): A revision of the genus Helotrephes STAL (Insecta: Heteroptera: Helotrephidae) with descriptions of twelve new taxa from the Oriental Realm. Annalen des Naturhistorischen Museums in Wien 100B: Addresses of the authors: DamirKOVAC Forschungsinstitut Senckenberg, Entomologie I Senckenberganlage 25, Frankfurt am Main, Germany dkovac@sng.uni-frankfurt.de Miroslav PAPÄCEK University of South Bohemia, Pedagogical Faculty Jeronymova Ceske Budejovice, Czech Republic papacek@pf.jcu.cz

6 270 ps Figs 1-6: Helotrephes steiningeri sp. n. 1 - propieural plate (right ventrolateral view, venter up); 2 - ventral midstemal carina (right lateral view, venter up), ps - prosternum, ms - mesostemum, mt - metasternum, 2, 3, 4, 5, 6- abdominal segment 2, 3, 4, 5, 6; 3 - aedeagus; 4 - right paramere; 5 - left paramere (figures 3-5: morphologically right view); 6 - female abdominal sternum 7 (ventral view, pilosity omited). Scale bar a = 1.0 mm (Figs 1, 2). Scale bar b = 0.5 mm (Figs 3a, 4a, 5), = 0.36 mm (Fig. 6), = 0.25 mm (Figs 3b, 4b).

7 271 Figs 7-12: 7-10: Helotrephes flaviceps rompinensis sp. n.; 11, 12: Hydrotrephes septentrional is. 7 - aedeagus; 8, 11 - right paramere: 9, 12 - left paramere (Figs 7-9, 11, 12 - morphologically right view); 10 - female abdominal sternum 7 (ventral view; white arrow indicates the same character that is presented also in H. flaviceps flaviceps, pilosity omited). Black arrows indicate differential characters from type subspecies (Figs 7-10) or type material respectively (Figs 11, 12). Scale bar = 0.5 mm (Figs 7a, 8a, 9, 1 lb, c, 12a, b), = 0.36 mm (Fig. 10), = 0.25 mm (Figs 8b, 12a), = mm (Fig. 7b).